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I’m trying label up a blank field with ‘yes’ or ‘no’ to the presence of names with either the word ‘Estuary’, ‘Loch’, or ‘Firth’ using * as a wildcard, in Field Calculator. I think I'm getting mixed up with SQL here... can anyone help?

The example of code I've used is:

arcpy.AddField_management(workingPath + "/GB_Catchment_merge.shp", "Offshore", "TEXT", "", "", 3)



expression = "LookUp( !MNCAT_NAME! )"
code_block = "def LookUp( a ):\n\

  if ( a == '*Estuary*' ):\n\

    return 'yes'\n\

  elif ( a == '*Loch*' ):\n\

    return 'yes'\n\

  elif ( a == '*Firth*.' ):\n\

    return 'yes'\n\

  else:\n\

    return 'no'"


arcpy.CalculateField_management(workingPath + "/GB_Catchment_merge.shp", "Offshore", expression, "PYTHON", code_block)
  • Do you want to use Calculate Field or are you ok with da.UpdateCursor instead? – BERA May 8 at 12:57
  • I have been using Field Calculator? – Cheekychives May 8 at 12:58
  • Have you tried LIKE instead of == ? – Bill Chappell May 8 at 13:05
  • Hi, I've just tried LIKE and it doesn't like it. – Cheekychives May 8 at 13:43
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I recommend using da.UpdateCursor instead of calculate field. The syntax is easier and unless you have many thousands of rows, the speed will match calculate field. You can try:

import arcpy, os

fc = os.path.join(workingPath,"GB_Catchment_merge.shp")
fields = ['MNCAT_NAME','Offshore']
yesses = ['Estuary','Loch','Firth']

with arcpy.da.UpdateCursor(fc, fields) as cursor:
    for row in cursor:
        if any([yes in row[0] for yes in yesses]): #row[0] is first field in fields list = MNCAT_NAME
            row[1] = 'yes'
        else:
            row[1] = 'no'
        cursor.updateRow(row)
  • 1
    Brilliant! It worked. Thank You! – Cheekychives May 8 at 13:46

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